public static class WebApiConfig    {        public static void Register(HttpConfiguration config)        {            var setting = System.Configuration.ConfigurationManager.AppSettings;            var cors = new EnableCorsAttribute("http://192.168.3.15:3000,http://192.168.3.15:3002", "*", "GET,POST,PUT,DELETE,OPTIONS")            {                SupportsCredentials = true            };            config.EnableCors(cors);            // Web API 路由            config.MapHttpAttributeRoutes();            config.Routes.MapHttpRoute(                name: "DefaultApi",                routeTemplate: "api/{controller}/",                defaults: new { id = RouteParameter.Optional }, constraints: new { id = @"\d+" }            );        }    }

  <system.webServer>    <httpProtocol>      <customHeaders>        <add name="Access-Control-Allow-Origin" value="http://192.168.6.43:3000" />         <add name="Access-Control-Allow-Headers" value="x-requested-with,content-type" />        <add name="Access-Control-Allow-Method" value="GET,POST,OPTIONS" />        <add name="Access-Control-Allow-Credentials" value="true" />      </customHeaders>    </httpProtocol>  </system.webServer>